1. Field of the Invention
The present invention relates to a detection apparatus and a method to control an operation of a manipulator comprising the detection apparatus in real time, the detection apparatus comprising of a single light beam irradiation device and a single monocular imaging camera mounted to a manipulator of a robot and the like, and the detection apparatus detecting a three-dimensional position of an object imaged by the camera.
2. Description of the Related Art
In recent years, it is becoming popular to use images imaged by a video camera and the like for a work of robot. Through the use of the imaged images, work object is identified or position and posture information of the work object are obtained to control operation of the robot.
It is, however, general to use a compound eye camera to obtain the three-dimensional position of the object. Camera is sometimes mounted around a robot hand. However, most of the times, camera is mounted external to the robot, mounted on a robot main body or mounted on a robot head.
Images imaged by monocular camera can be made to pseudo three-dimensional images. This is realized by selecting and fixing a perspective frame to give depth to the images. Also, as long as a distance from a camera to an objective plane is known, even an image from front can be made to a three-dimensional image. By processing such images, work such as fast picking is performed.
An industrial robot is intended to enhance productivity. To this end, the industrial robot is imposed to improve operating speed and to accurately repeat operation. To make the robot work, it is necessary to deliver and receive the work object in a fixed manner. However, it is sometimes difficult, due to increasing costs, to machinery prepare position and posture of the object to deliver the robot. In this case, information such as the posture and position of the object are obtained through the use of the imaged images to solve the problem.
Images imaged by the video camera are sequential images. In the prior described above, however, perform operation control of robot by segmenting one of the sequential images. This does not make good use of a temporal change, which is a feature of the continuous image.
The temporal change of the sequential images relates to a quality of work of robot, including detecting pickup failure of the work object or monitoring work completion. The industrial robot should solve these problems in the future.
Some complicated processes are required and a considerable analysis time (about 0.4 seconds) is taken to obtain the three-dimensional information from two-dimensional imaged image when the compound eye camera is used. This is why one of the continuous image is used. Through the use of the monocular camera, however, three-dimensional information is obtained by fixing imaging frame (camera) and recognizing distance from a camera to an objective photographed plane.
When the compound eye camera is used, there is a flexibility in the imaging frame though, it takes time for processing. On the other hand, when the monocular camera is used, the imaging frame is fixed but it takes less time for processing. This relates to time for detecting distance to the objective photographed plane.
Japanese Patent Application Laid-Open No. 2011-257267 discloses a method for detecting a distance from the objective photographed plane to a focal of the camera and a direction of the objective photographed plane in real time. The distance and the direction are detected through the use of the monocular camera mounted to the hand and three light beams. It is, however, difficult to detect arrangement of devices and adjust the arrangement so as to apply a mathematical expression. Further, detection of the work object and operation control of the hand are problems to be solved in the future.